This invention generally relates to an outlet valve assembly for controlling the discharge of fluid under pressure from a chamber, particularly a pumping chamber of a paint sprayer, and, more particularly, to such an outlet valve assembly which provides for reduced wear and increased life of the outlet valve without adversely affecting valve operation.
One form of paint sprayer in widespread use utilizes a diaphragm pump to draw paint or other fluid being pumped through an inlet valve assembly into a fluid chamber where the fluid is pressurized and discharged therefrom through an outlet valve assembly to a paint sprayer gun or the like.
The current state of the art outlet valve assembly for such a sprayer pump includes a light return spring and a fixed stop for limiting the travel of the outlet valve away from the valve seat during opening of the outlet valve. Such a fixed stop reduces the amount of time required to return the outlet valve to its fully seated or shut-off position prior to the start of the inlet stroke to minimize the back flow through the outlet valve, which is very important in obtaining optimum volumetric efficiency in such a sprayer pump.
Heretofore, the fixed stop was usually made of hardened steel or the like to reduce peening caused by the high speed and rapid impact of the outlet valve against the stop during the pumping operation. Typically, a sprayer pump of this type is driven by an electric motor which operates at approximately 1750 revolutions per minute (rpm). The resulting rapid impact of the outlet valve against the fixed stop, together with the abrasive particles in latex paint and the like, cause the rigid stop to wear and increase the distance that the outlet valve travels. Also, the impact of the outlet valve against the fixed stop may cause excessive wear of the outlet valve and cause the outlet valve to become out of round, resulting in increased leakage at the outlet valve and reduced pump efficiency.